/**
 *    Copyright 2009-2015 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.apache.ibatis.executor.keygen;

import java.sql.Statement;

import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;

/**
 * @author Clinton Begin
 */
/**
 * 键值生成器
 *
 */
public interface KeyGenerator {

	// 定了2个回调方法，processBefore,processAfter
	/**
	 * 执行insert之前，设置属性order="BEFORE"，先执行查询key，并设置到参数对象中
	 * 
	 * @param executor 执行器
	 * @param ms	映射的语句
	 * @param stmt 语句 
	 * @param parameter 参数
	 */
	void processBefore(Executor executor, MappedStatement ms, Statement stmt, Object parameter);

	/**
	 * 执行insert之后，设置属性order="AFTER"，表示执行后，再查一遍key，
	 * 
	 * @param executor 执行器
	 * @param ms	映射的语句
	 * @param stmt 语句 
	 * @param parameter 参数
	 */
	void processAfter(Executor executor, MappedStatement ms, Statement stmt, Object parameter);

}
